miRNAs differentially expressed in prostate cancer cell lines after soy treatment

MicroRNAs (miRNAs) are small non-coding RNAs that have aberrant expression in prostate cancer tissues. miRNAs are involved in the initiation and progression of cancer, and several miRNAs have been characterized as tumor suppressors or oncogenes. It has been shown that some miRNAs can be directly regulated from their own promoters by epigenetic alterations in cancer cells. Moreover, phytoestrogens are known to have epigenetic action on gene transcription. Hence, we conducted here an examination of the miRNA expression profile in human prostate cancer cell lines after soy phytoestrogen treatment. The comparative miRNA expression profiles of prostate cell lines (PC-3, DU145, LNCaP) after a 48-h treatment of 40 μM genistein, 110 μM daidzein, or 2 μM 5-azacytidine (5-AZA, a demethylating agent) were conducted with a Taqman low-density array. We found that out of 377 miRNAs tested, 180, 170 and 150 miRNAs were amplified with 2% of variation in the triplicate in PC-3, DU145 and LNCap cells, respectively, and only 5 miRNAs for PC-3 and DU145 cells and 4 miRNAs for LNCap exhibited a significant change in their expression. Treatment with genistein or daidzein had similar effects on miRNA regulation to those of 5-AZA treatment. This work demonstrated a new role of isoflavones on the regulation of miRNAs in prostate cancer.